Young-Seog Kim

Young-Seog Kim
Pukyong National University · Department of Earth and Environmental Sciences

PhD

About

433
Publications
83,944
Reads
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6,811
Citations
Additional affiliations
March 2006 - present
Pukyong National University
Position
  • Professor (Full)
October 1996 - May 2001
University of Southampton
Position
  • PhD Student
Education
March 1984 - February 1990
Seoul National University
Field of study
  • Department of Geological Sciences

Publications

Publications (433)
Article
Full-text available
COSINE-100 is a direct detection dark matter experiment that aims to test DAMA/LIBRA’s claim of dark matter discovery by searching for a dark-matter-induced annual modulation signal with NaI(Tl) detectors. We present new constraints on the annual modulation signal from a dataset with a 2.82 yr livetime utilizing an active mass of 61.3 kg for a tota...
Article
Full-text available
The AMoRE collaboration is preparing for the AMoRE-II experiment that will probe neutrinoless double beta decay with 100 kg of ¹⁰⁰Mo isotope. The ¹⁰⁰Mo nuclide will be mainly in the form of lithium molybdate crystals that are instrumented with metallic magnetic calorimeters (MMC), which detect the phonon excitations produced by electrons from neutr...
Article
Full-text available
The advanced Mo-based rare process experiment (AMoRE) is an international project searching for the neutrinoless double beta (0νββ) decay of 100Mo using low-temperature calorimetric detection of heat and light signals based on magnetic microcalorimeter (MMC) readouts. Li2MoO4 crystals have been considered as the main target crystals for the second...
Preprint
Full-text available
The DAMA/LIBRA collaboration has reported the observation of an annual modulation in the event rate that has been attributed to dark matter interactions over the last two decades. However, even though tremendous efforts to detect similar dark matter interactions were pursued, no definitive evidence has been observed to corroborate the DAMA/LIBRA si...
Article
Full-text available
In the last several years, considerable progress has been made in reducing or eliminating noise in ellipsometric spectra, including the development of algorithms for eliminating endpoint-discontinuity artifacts, a reciprocal-space expression for quantifying the effectiveness of linear filters, and the corrected maximum-entropy (CME) approach for el...
Article
The AMoRE collaboration is preparing for the second phase of the experiment, AMoRE-II, which will exploit a 100 kg of ¹⁰⁰ Mo isotopes to search for neutrinoless double beta decay from the isotope. Most of the ¹⁰⁰ Mo isotopes will be contained in the lithium molybdate (Li 2 MoO 4 ) crystals, which will act as absorbers of cryogenic calorimeters coup...
Article
A search for the neutrinoless quadruple beta decay of ¹³⁶Xe was conducted with the liquid-xenon detector XMASS-I using 327 kg ×800.0 days of the exposure. The pulse shape discrimination based on the scintillation decay time constant which distinguishes γ-rays including the signal and β-rays was used to enhance the search sensitivity. No significant...
Article
Full-text available
Gasado Island, on the southwestern Korean Peninsula, comprises c. 50 Ma volcanic rocks that are cut by faults and fractures hosting low-sulfidation epithermal Au-Ag mineralization. In this study, we examined the relationship between the fault-fracture networks and auriferous vein systems to better understand the role of brittle structures in contro...
Preprint
A search for the neutrinoless quadruple beta decay of $^{136}$Xe was conducted with the liquid-xenon detector XMASS-I using $\rm 327\; kg \times 800.0 \; days$ of the exposure. The pulse shape discrimination based on the scintillation decay time constant which distinguishes $\gamma$-rays including the signal and $\beta$-rays was used to enhance the...
Article
In seismic hazard assessment, subsurface geophysical surveying has gained popularity in recent years towards fault mapping and determining seismic deformation parameters such as fault offset, recurrence, and depth of fault, locating proper trench sites based on the subsurface information. In the present study, electrical resistivity tomography (ERT...
Preprint
Full-text available
Neutrino Elastic scattering Observation with NaI (NEON) is an experiment designed to detect neutrino-nucleus coherent scattering using reactor electron antineutrinos. NEON is based on an array of six NaI(Tl) crystals with a total mass of 13.3 kg, located at the tendon gallery that is 24 m away from a reactor core with a thermal power of 2.8 GW in t...
Article
Sodium molybdate crystals are excellent scintillating target material that can be used to investigate the neutrinoless double beta decay of ¹⁰⁰ Mo. Because this material contains Na nuclei, it could also be used to clarify the contribution of Na in the controversial claim of dark matter observation by the DAMA/LIBRA experiment. Recent developments...
Article
Full-text available
We report on the search for weakly interacting massive particle (WIMP) dark matter candidates in the galactic halo that interact with sodium and iodine nuclei in the COSINE-100 experiment and produce energetic electrons that accompany recoil nuclei via the the Migdal effect. The WIMP mass sensitivity of previous COSINE-100 searches that relied on t...
Article
Full-text available
The COSINE-100 experiment is designed to test the DAMA experiment which claimed an observation of a dark matter signal from an annual modulation in their residual event rate. To measure the 1 %-level signal amplitude, it is crucial to control and monitor nearly all environmental quantities that might systematically mimic the signal. The environment...
Article
Full-text available
Since α-SnS has optically strong anisotropic characteristics, a simple method to determine its crystal orientation is strongly needed in device engineering. In this report, by measuring dielectric function ε = ε1 + iε2 of α-SnS in the 1–5 eV spectral region with the full azimuthal angle range, we could find a simple relationship between measured di...
Preprint
Full-text available
We report on the search for weakly interacting massive particle (WIMP) dark matter candidates in the galactic halo that interact with sodium and iodine nuclei in the COSINE-100 experiment and produce energetic electrons that accompany recoil nuclei via the the Migdal effect. The WIMP mass sensitivity of previous COSINE-100 searches that relied on t...
Article
Full-text available
We present a background model for dark matter searches using an array of NaI(Tl) crystals in the COSINE-100 experiment that is located in the Yangyang underground laboratory. The model includes background contributions from both internal and external sources, including cosmogenic radionuclides and surface $$^{210}$$ 210 Pb contamination. To build t...
Article
Fractures (including faults and joints) are important pathways for magma in the upper crust. Two theories of dyke intrusion are generally accepted: dykes open pre-existing fractures or dykes inject propagating new fractures at their tips. Thus, there is a close interrelationship between dyke intrusion and fractures. We present a field-based study f...
Article
Full-text available
We report the identification of metastable isomeric states of $$^{228}$$ 228 Ac at 6.28 keV, 6.67 keV and 20.19 keV, with lifetimes of an order of 100 ns. These states are produced by the $$\beta $$ β -decay of $$^{228}$$ 228 Ra, a component of the $$^{232}$$ 232 Th decay chain, with $$\beta $$ β Q-values of 39.52 keV, 39.13 keV and 25.61 keV, resp...
Preprint
Searches for neutrinoless double beta decay generally require ultimate low backgrounds. Surface $\alpha$ decays on the crystals themselves or nearby materials can deposit a continuum of energies that can be as high as the $Q$-value of the decay and may cover in the region of interest (ROI). The AMoRE-Pilot experiment is an initial phase of the AMoR...
Preprint
Full-text available
The COSINE-100 experiment is designed to test the DAMA experiment which claimed an observation of a dark matter signal from an annual modulation in their residual event rate. To measure the 1 %-level signal amplitude, it is crucial to control and monitor nearly all environmental quantities that might systematically mimic the signal. The environment...
Article
Full-text available
We report the dielectric tensors on the cleavage plane of biaxial SnSxSe1-x alloys in the spectral energy region from 0.74 to 6.42 eV obtained by spectroscopic ellipsometry. Single-crystal SnSxSe1-x alloys were grown by the temperature-gradient method. Strongly anisotropic optical responses are observed along the different principal axes. An approx...
Article
This paper describes the liquid scintillator veto system for the COSINE-100 dark matter experiment and its performance. The COSINE-100 detector consists of eight NaI(Tl) crystals immersed in 2200 L of linear alkylbenzene-based liquid scintillator. The liquid scintillator tags between 65 and 75% of the internal ⁴⁰K background in the 2–6 keV energy r...
Preprint
Full-text available
It is a long-standing debate as to whether or not the annual modulation in the event rate observed by the DAMA sodium iodide experiment is caused by the interaction of dark matter particles. To resolve this issue, several groups have been working to develop new experiments with the aim of reproducing or refuting DAMA's results using the same sodium...
Article
Full-text available
It is a long-standing debate as to whether or not the annual modulation in the event rate observed by the DAMA sodium iodide experiment is caused by the interaction of dark matter particles. To resolve this issue, several groups have been working to develop new experiments with the aim of reproducing or refuting DAMA's results using the same sodium...
Article
We report the discovery of two metastable isomeric states of 228Ac at 6.28\,keV and 20.19\,keV, with lifetimes of 299±11\,ns and 115±25\,ns, respectively. These states are produced by the β-decay of 228Ra, a component of the 232Th decay chain, with β Q-values of 39.52\,keV and 25.61\,keV, respectively. Due to its low Q-value as well as the relative...
Preprint
Full-text available
We report the discovery of two metastable isomeric states of $^{228}$Ac at 6.28\,keV and 20.19\,keV, with lifetimes of 299$\pm$11\,ns and 115$\pm$25\,ns, respectively. These states are produced by the $\beta$-decay of $^{228}$Ra, a component of the $^{232}$Th decay chain, with $\beta$ Q-values of 39.52\,keV and 25.61\,keV, respectively. Due to its...
Article
COSINE-100 is a dark matter detection experiment that uses NaI(Tl) crystal detectors operating at the Yangyang underground laboratory in Korea since September 2016. Its main goal is to test the annual modulation observed by the DAMA/LIBRA experiment with the same target medium. Recently DAMA/LIBRA has released data with an energy threshold lowered...
Article
Searches for new physics push experiments to look for increasingly rare interactions. As a result, detectors require increasing sensitivity and specificity, and materials must be screened for naturally occurring, background-producing radioactivity. Furthermore, the detectors used for screening must approach the sensitivities of the physics-search d...
Article
We performed a search for event bursts in the XMASS-I detector associated with 11 gravitational-wave events detected during LIGO/Virgo’s O1 and O2 periods. Simple and loose cuts were applied to the data collected in the full 832 kg xenon volume around the detection time of each gravitational-wave event. The data were divided into four energy region...
Preprint
Full-text available
We present a background model for dark matter searches using an array of NaI(Tl) crystals in the COSINE-100 experiment that is located in the Yangyang underground laboratory. The model includes background contributions from both internal and external sources, including cosmogenic radionuclides and surface $^{210}$Pb contamination. To improve the mo...
Article
Full-text available
We report the parameter values of the model dielectric function (\(\varepsilon = \varepsilon_{1} + i\varepsilon_{2}\)) of SnS0.52Se0.48 in the spectral range from 0.74 to 6.42 eV and the temperature range from 27 to 350 K. An analytic representation, obtained using the Tauc–Lorentz (TL) dispersion model, allows interpolation of the parameters with...
Article
Full-text available
We present the principal components of the dielectric tensor for α-SnSe biaxial single crystal in the spectral range from 0.74 to 6.42 eV at room temperature (300 K) using spectroscopic ellipsometry. Aspnes’ first-order approximation method was applied to obtain approximated pseudodielectric response from the pseudodielectric tensor measured at an...
Article
The Advanced Molybdenum-based Rare process Experiment (AMoRE) in its second phase will search for neutrinoless double-beta (0ν β β) decay of ¹⁰⁰Mo in 200 kg of molybdate crystals. To achieve the zero-background level in the energy range of the double-beta decay Q-value of ¹⁰⁰Mo, the radioactive contamination levels in AMoRE crystals should be low....
Article
Pb208 is a doubly magic nucleus which has been studied extensively by many experiments and nuclear models. Its properties, such as excitation energies, spins, and parities of the ground and excited states are well known. However, some γ transitions with Eγ>3 MeV from the excited states to the ground state in Pb208 have never been observed. The inte...
Article
Pulse-shape discrimination plays a key role in improving the signal-to-background ratio in NEOS analysis by removing fast neutrons. Identifying particles by looking at the tail of the waveform has been an effective and plausible approach for pulse-shape discrimination, but has the limitation in sorting low energy particles. As a good alternative, t...
Article
Full-text available
We present parameters that allow the dielectric function (eps=eps_1 + i*eps_2) of perovskite SrTiO 3 (STO) to be calculated for spectral range from 0.74 to 6.42 eV and temperatures from 26 to 674 K. The data of STO were reproduced from a previous report. We use the Tauc-Lorentz model to express of STO analytically for each temperature. The spectra...
Article
Full-text available
Abstract We report the temperature dependence of the dielectric function ε = ε 1 + iε 2 and critical point (CP) energies of biaxial α-SnS in the spectral energy region from 0.74 to 6.42 eV and temperatures from 27 to 350 K using spectroscopic ellipsometry. Bulk SnS was grown by temperature gradient method. Dielectric response functions were obtaine...
Preprint
Full-text available
Pulse shape discrimination plays a key role in improving the signal-to-background ratio in NEOS analysis by removing fast neutrons. Identifying particles by looking at the tail of the waveform has been an effective and plausible approach for pulse shape discrimination, but has the limitation in sorting low energy particles. As a good alternative, t...
Preprint
The Advanced Molybdenum-based Rare process Experiment in its second phase (AMoRE-II) will search for neutrinoless double-beta (0{\nu}\b{eta}\b{eta}) decay of 100Mo in 200 kg of molybdate crystals. To achieve the zero-background level in the energy range of the double-beta decay Q-value of 100Mo, the radioactive contamination levels in AMoRE crystal...
Preprint
Searches for new physics push experiments to look for increasingly rare interactions. As a result, detectors require increasing sensitivity and specificity, and materials must be screened for naturally occurring, background-producing radioactivity. Furthermore the detectors used for screening must approach the sensitivities of the physics-search de...
Article
Full-text available
The annual modulation signal observed by the DAMA experiment is a long-standing question in the community of dark matter direct detection. This necessitates an independent verification of its existence using the same detection technique. The COSINE-100 experiment has been operating with 106 kg of low-background NaI(Tl) detectors providing interesti...
Article
NaI(Tl) crystals are used as particle detectors in a variety of rare-event search experiments because of their superb light-emission quality. The crystal light yield is generally high, above 10 photoelectrons per keV, and its emission spectrum is peaked around 400 nm, which matches well to the sensitive region of bialkali photocathode photomultipli...
Article
Full-text available
We have searched for exotic neutrino-electron interactions that could be produced by a neutrino millicharge, by a neutrino magnetic moment, or by dark photons using solar neutrinos in the XMASS-I liquid xenon detector. We observed no significant signals in 711 days of data. We obtain an upper limit for neutrino millicharge of 5.4×10−12e at 90% conf...
Article
Full-text available
We report parametric modeling of the optical properties of monolayer WS2 so its dielectric response can be calculated at temperatures from 41 to 300 K from 1.5 to 6 eV. Parameterization of dielectric function was performed by dielectric-function parametric model, using previously reported dielectric function data which was obtained by spectroscopic...
Preprint
We performed a search for event bursts in the XMASS-I detector associated with 11 gravitational-wave events detected during LIGO/Virgo's O1 and O2 periods. Simple and loose cuts were applied to the data collected in the full 832 kg xenon volume around the detection time of each gravitational-wave event. The data were divided into four energy region...
Preprint
Full-text available
We investigate analytically the anisotropic dielectric properties of single crystal {\alpha}-SnS near the fundamental absorption edge by considering atomic orbitals. Most striking is the excitonic feature in the armchair- (b-) axis direction, which is particularly prominent at low temperatures. To determine the origin of this anisotropy, we perform...
Preprint
We successfully developed a new photomultiplier tube (PMT) with a three-inch diameter, convex-shaped photocathode, R13111. Its prominent features include good performance and ultra-low radioactivity. The convex-shaped photocathode realized a large photon acceptance and good timing resolution. Low radioactivity was achieved by three factors: (1) the...
Preprint
Full-text available
COSINE-100 is a dark matter search experiment that uses NaI(Tl) crystal detectors operating at the Yangyang underground laboratory in Korea since September 2016. Its main goal is to test the annual modulation observed by the DAMA/LIBRA experiment with the same target medium. Recently DAMA/LIBRA has released data with an energy threshold lowered to...
Article
Full-text available
We report measurements of annual and diurnal modulations of the cosmic-ray muon rate in the Yangyang underground laboratory (Y2L) using 952 days of COSINE-100 data acquired between September 2016 and July 2019. A correlation of the muon rate with the atmospheric temperature is observed and its amplitude on the muon rate is determined. The effective...
Preprint
We have searched for exotic neutrino-electron interactions that could be produced by a neutrino millicharge, by a neutrino magnetic moment, or by dark photons using solar neutrinos in the XMASS-I liquid xenon detector. We observed no significant signals in 711 days of data. We obtain an upper limit for neutrino millicharge of 5.4$\times$10$^{-12} e...
Preprint
Full-text available
The AMoRE collaboration searches for the neutrinoless double-beta decay of 100Mo with ultra-radiopure molybdate crystals operated as low-temperature scintillating bolometers. For such a rare event search experiment, the techniques for investigating and reducing radioactive background contaminants in detector materials are extremely crucial. This pa...
Preprint
The Center for Underground Physics (CUP) of the Institute for Basic Science (IBS) is searching for the neutrinoless double-beta decay (0{\nu}\b{eta}\b{eta}) of 100Mo in the molybdate crystals of the AMoRE experiment. The experiment requires pure scintillation crystals to minimize internal backgrounds that can affect the 0{\nu}\b{eta}\b{eta} signal....
Article
Full-text available
The complex dielectric function ɛ = ɛ1 + iɛ2 of monolayer tungsten disulfide (WS2) is investigated for the energy range from 1.5 to 6.0 eV and temperatures from 41 to 300 K. Measurements were performed under ultra-high vacuum conditions to avoid degradation and overlayer contamination. Fourteen critical-point (CP) energies were observed and their o...
Article
As a possible precursor of earthquakes, major ions, stable water isotopes and trace elements of groundwater and spring water have been monitored and analyzed for twenty years and mechanisms for the variations of hydrogeochemistry of groundwater have been suggested over the world. Although numerous physical variations associated with earthquakes are...
Preprint
The annual modulation signal observed by the DAMA experiment is a long standing question in the community of dark matter direct detection. This necessitates an independent verification for its origin using the same detection technique. The COSINE-100 experiment has been operating with 106~kg of low-background NaI(Tl) detectors providing interesting...
Preprint
Full-text available
This paper describes the liquid scintillator veto system for the COSINE-100 dark matter experiment and its performance. The COSINE-100 detector consists of 8 NaI(Tl) crystals immersed in 2,200~L of linear alkylbenzene based liquid scintillator. The liquid scintillator tags between 65 and 75\% of the internal $^{40}$K background in the 2--6~keV ener...